She started with a job as a picture researcher when she first came to London after University, before taking off to travel in her 20s.

“I managed to work as a photo editor for a magazine in Australia then Hong Kong, and started using my skills in different ways,” she said.

When she returned to the UK she had a stint working for the Daily Mail’s “paparazzi guy” before returning to the agency she worked for previously, which was encouraging photographers to get into stock photography.

“I went out to work with photographers to see how much money they were making,” she said. “I started with one, then collected quite a few, and decided I could go out on my own.”

She set up her first company, Banana Stock, which she then sold in 2004. Two years later, she started the company she currently owes her success to, Monkey Business.

“We’re a production company — we produce stock photography and video and travel around the world doing it,” she said. “[We work] in a team of about 10. I think up what we’re going to shoot — you run your own show and decide what to do. You’re as good as your pictures,” she said.

What should you shoot?

“The big money is in business, education, lifestyle, medical — anything that happens in life, if you take a picture or video of it, people need it,” she said. “It’s about making it as natural as you can. I’m always looking at what’s going on on TV and natural life.”

Danny Groner, manager of blogger partnerships and outreach at Shutterstock, told Business Insider: “If people ask us what we’re looking for, we tell them to shoot their authentic lives and what inspires them. At the same time, many contributors tend to be data-driven, which is where reports like the ones above come in. They look at what’s popular in their portfolios and in what others are selling, and they make more of it.”

In terms of models, Yeulet uses agencies or talent sites like StarNow. “When we go abroad we use big casting network sites,” she said. “It used to be all glamorous but now advertisers want more normal [models]. I use my kids and their friends. We’ve even gone into old peoples’ homes and put adverts up.”

“You have to produce something that a lot of people like — include different styles and ethnicities,” she added.

Where should you shoot?

Yeulet’s most frequented destinations include the UK, the US, and South Africa.

“South Africa is great for UK winter, because you get their summer,” she said. “Capetown is an amazingly beautiful place. It’s strange — you get so many teams down there shooting and getting ready for the European summer.”

The most difficult place to shoot is South America, according to Yeulet. “We went to Argentina and recently Brazil,” she said. “[Brazil is] more difficult — they have rules about models, and if you do a shoot there they want you to have armed guards with you. Argentina is a bit like that — men smoking and telling you you have to shoot a certain way.”

Not all shoots are done on location, however — one of Cathy’s highest selling photos, shown below, was taken at a local festival using her older kids and friends as models.

Monkey BusinessThis picture, one of the highest selling for Cathy, was taken at a local festival using her older kids and friends as models.

She added that sometimes the team choose a place for a shoot simply because it’s on their travel bucket list.

“I’ve been to Ibiza a few times because everyone likes going there,” she said. “They have a load load of models who work in the clubs — we go shoot them early in the morning when they finish, or before they start at night.”

How much can you earn?

“We’re well into the millions, but we’re one of the top production companies,” she said. “You can make stock from being a single photographer using your children. Plenty of people do that and have it as a nice hobby.”

She said that on Shutterstock, a basic subscription will give you around 39p per image sold. According to the company, there have been more than 500 million paid downloads to date, and five images are sold per second. They added that more than $US400 (£320) million has been paid to contributors since 2003.

The majority — $US59.3 (£46.6) million worth — of contributors came from Europe, with the UK ranking fifth globally in terms of amount paid at $US4.2 (£3) million.

“The difference between the old model [where a photo could sell for $US500 (£400)] is that now you sell crazy amount of images for less money,” Yeulet said. Also, as your earnings on the site increase, the amount you earn per download increases, too.

This shot, taken in her back garden, is one of her top sellers — making over £10,000 so far — and continues to make money.

“It’s like [vinyl] sales — they sell over and over again,” she said. A good image might make £6,000 over time if it does really well, but then you may get some that sell less. It all evens out.”

She added that while when she set out the industry was full of professional producers, digital photography has changed everything.

“Some people earn a really nice amount of money and flip from being part time to full time,” she said.”It’s the gift that keeps giving if you’ve got the right products and the right subjects. You make your initial investment and it keeps coming back. New technology and fashion allows you to redo stuff. I can’t always believe how much you can keep producing.”

So what should you do to get started?

“Pick a few of your best shots and make a little portfolio,” Yeulet said. “Think about relationship going on in pictures.”

Then sign up on a site like Shutterstock. If they like your photos, they will sign you up and provide feedback going forward. “To apply to become a contributor, we ask people to submit a batch of 10 images, and if one gets approved, they are accepted,” Groner said.

“They will receive feedback on the others, and are encouraged to continue to hone their skills as they grow in their photography. They’re evaluated on both the beauty of the photo as well as the aesthetic — we want well-composed, well-lit images, for example,” he said.

“We stay in touch with contributors regularly through email, blog posts, and a Twitter feed directly speaking to them with requests for content,” Groner added. “This creates a feedback loop.”

“You’re as good as every shot you put on,” Yeulet added. “If you listen and learn to what your editor is telling you, you’ll soon learn what they like. If people like them they will sell the next day.”

She added that you should always choose your best work to upload, and try and develop your own style.

“Don’t look too much at what other people are doing,” she said. “It’s really important to say ‘This is me, this is how I’m going to do this, and create a style.”